Ron,
It's your call of course. From what I've gleaned over the air and from
the net, the ALS-600 doesn't seem to have the same problem as I had
with my THP. This will no doubt vary from radio to radio, amp to amp,
and operator to operator.
I'm not sure it's from the Bible, but the old adage says: "If it be not
broke, fixeth it not".
My amp seems to be pretty sensitive to such things as over drive, and
so I had it done.
73, Steve KW3A
On 7/2/2014 6:10 PM, Dr. Ronald E. Milliman wrote:
> Steve, thanks for the heads-up re the TS-590 mod. I purchased mine new last
> November; so, evidently, if I operate my ALS-600 with it, I really should
> have the mod installed.
>
> Ron, K8HSY
>
>
>
> -----Original Message-----
> From: For blind ham radio operators [mailto:[log in to unmask]]
> On Behalf Of Steve Forst
> Sent: Wednesday, July 02, 2014 1:10 PM
> To: [log in to unmask]
> Subject: Kenwood TS-590 ALC mod
>
> Not sure if anyone else on the list has had this done, but figured I
> would share my experience.
>
> First, don't take anything I say as Gospel, confirm with another source.
>
> The 590 has had a known issue of ALC/power spike and Kenwood is now
> offering a free mod to fix. You need to send the radio to a Kenwood
> service center at your expense, and Kenwood covers the mod and return
> shipping.
>
> If this spike exists on a particular radio, it could cause a solid state amp
> (or some high end tube amps) to trip their protection circuit.
> Many solid state amp owners have reported no problems and all works
> well. others, like me, found the amp tripped with only modest drive.
>
> in my case my THP 1.2kfx which should put out 750 watts pep, with a
> drive between 75-90 watts, would trip off with much less. On 10
> meters I was limited to about 35 watts drive, 40 watts on 15, and 50 or
> so on 20 meters. Lower bands could handle 60 watts. More drive and
> the amp would trip.
>
> Sent mine out in June to the Virginia Beach service center and had it
> back in 12 days. Have had it back for a week and have run it with the
> ss amp and no problems. Played some in the Canada Day contest on both
> 15 and 20 meters running 70 watts drive and no problems. THP is out of
> business now and this amp would be expensive to repair, so I will probably
> limit drive to 65-70 watts and hopefully the extra headroom will give it a
> longer life. I'll treat it like a 550 - 600 watt amp instead of 750.
>
> So I was happy with the result. Your mileage may vary. The mod
> consists of some hardware changes and some changes in the alignment
> procedure. If your 590 was built starting in January 2014, the changes
> were implemented at the factory. Anything built from 2010 - 2013 can
> get the mod if you desire. Obviously most of these radios are long
> out of warranty, but kenwood is treating this as a warranty repair.
> Mine was built in April 2011 and purchased in June 2011.
>
> Anyway, that's my long winded story.
>
> 73, Steve KW3A
>
>
>
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